Single-Step Lignin-Derived Ultramicroporous Carbon Membranes Eradicating Spontaneous Combustion for Efficient Pt Single-Atom Catalysis in Ambient Formaldehyde Oxidation

We present a single-step approach for producing ultra-microporous carbon membranes from lignin that eliminates spontaneous combustion during carbonization. A CO 2 -assisted electrospinning converts in situ NaOH→Na 2 CO 3 , enabling high-temperature self-activation without corrosive external agents. DFT further rationalizes CO-facilitated Na desorption, explaining the combustion-free carbonization. The resulting carbon membranes possess ultra-high surface area (2443 m 2 ·g -1 ) and narrowly distributed ultra-micropores (∼0.5 nm). At ultra-low Pt loadings (0.01 wt%), aberration-corrected HAADF-STEM and CO-pulse chemisorption reveal near single-atom dispersion (∼0.57 nm). The MC-Pt 0.01 (0.01 wt% Pt/microporous carbon) catalyst achieves 47.4% HCHO degradation at room temperature (70 ppm, 2 h, static) and 965 min fully penetrated with 262.5 mg·g -1 capacity (12 ppm, GHSV = 4000 L·g cat -1 ·h -1 ). Mechanistic analyses (EPR, O 2 -TPD, in situ DRIFTS) support a dual-site pathway, wherein vacancy-enriched ultra-micropores chemisorb HCHO, while atomically dispersed Pt activates O 2 to generate •O 2 - , driving complete mineralization to CO 2 . This strategy integrates waste-derived carbons with low-precious-metal catalysis, offering strong potential for sustainable indoor air purification and environmental remediation.